The present disclosure generally relates to well screen assemblies used in the oil and gas industry and, more specifically, to well screen assemblies that include an erosion resistant screen section for use in gravel packing or frac-packing operations.
In hydrocarbon-producing wells, loosely or unconsolidated portions of a subterranean formation (e.g., sand, rock, or other particulates) may be produced with formation fluids. These unconsolidated particulates may adversely affect production equipment and operations, increasing expense and operator and/or wellbore downtime. For example, production of the unconsolidated particulates may result in, among other things, severe erosion of wellbore tubulars (e.g., production tubing) and partial or complete blockage of the flow of formation fluids for recovery. Producing unconsolidated particulates often requires costly workover jobs, and can sometimes lead to caving or collapse of casing sections.
One approach to prevent or reduce the unconsolidated particulates from being produced with the formation fluids is the use of a gravel packing or frac-packing treatment. In a typical gravel packing treatment, one or more screens are mounted on a wellbore tubular and positioned in a wellbore drilled through a subterranean formation adjacent a desired production interval. An annulus is formed between the subterranean formation and the wellbore tubular. Specifically sized particulate material, referred to herein collectively as “gravel,” is pumped as a slurry through the wellbore tubular and into the annulus. Some of the liquid in the slurry flows through the screens and into the wellbore tubular at one or more flow ports provided in the wellbore tubular. A portion of the liquid may also flow into the subterranean formation for treatment operations (e.g., hydraulic fracturing, etc.). The gravel is deposited into the annulus around the screen and tightly packed therein to form a “gravel pack.” The gravel is sized such that it forms a permeable mass that allows formation fluids therethrough but at least partially prevents or blocks the flow of unconsolidated particulates with the formation fluids.
As used herein, the term “frac-packing” refers to a combined hydraulic fracturing and gravel packing treatment. In a typical frac-packing treatment, a fluid is pumped through the annulus between a wellbore tubular mounted with a well screen and a wellbore in a subterranean formation. The fluid includes particulate matter, such as proppant and/or gravel, and is pumped into various perforations that have been defined through casing that lines the wellbore. In the case of open hole completions, the fluid slurry is pumped directly into the wellbore perforations. The fluid slurry is pumped at a rate and pressure sufficient to create or enhance at least one fracture in the surrounding formation, and the proppant and/or gravel is flowed into the created fractures and serves to keep them open during production.
Once a desired amount of hydraulic fracturing in the formation has been achieved, fluids are then drawn through the well screens to be returned to the surface. This process causes the gravel to dehydrate and pack against the well screens. The fluids will tend to follow the path of least resistance, which causes the liquid to flow to the screen sections not covered in gravel, which are typically the upper portions of the well screens. The decrease in flow area through the well screen increases the fluid velocity and pressure. As the gravel covers the last bit of the well screen, commonly referred to as “screen out,” the pressure spikes and pumping is stopped. This increase in fluid velocity and pressure at screen out can result in the remaining portions of the screens that are not covered in gravel to experience erosion or deformation that may result in screen failure. Screen failure may result in gravel from the gravel pack and/or other formation unconsolidated particulates being produced to the surface.
To reduce the possibility of screen failure, the rate of return through the screens when forming the gravel pack is typically reduced or otherwise limited. However, limited return rates may result in, among other things, a longer period before the well can be brought on and a greater amount of fluid required in the slurry.